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If ever a single keystone animal specieswere to be identified with the prairieecosystems of North America, the

black-tailed prairie dog (Cynomys ludovi-cianus) would probably most easily qualify.Keystone species are those animals thattend to hold an ecosystem together, andwhose presence or absence has the greatesteffect on the well-being of the otherspecies. In various ways it can be arguedthat predators such as the black-footed fer-ret (Mustela nigripes), swift fox (Vulpesvelox), coyote (Canis latrans), Ferrugi-nous Hawk, Golden Eagle, and prairierattlesnake (Crotalus v. viridis) alllargely or partly depended histori-cally on the black-tailed prairiedog as prey. The ecological ef-fects of prairie dogs on sur-rounding vegetation arealso exploited by MountainPlover, Horned Lark, vari-ous ground squirrels(Spermophilus spp.), andgrasshopper mice (Ony-chomys spp.). Theprairie dogs’ aban-doned burrows areused by horned lizards(Phrynosoma spp.), spade-foot toads (Spea spp.), tiger sala-manders (Ambystoma tigrinum), and a vari-ety of invertebrates. Perhaps no otherNorth American animal can claim so manyuninvited guests as the prairie dog, andperhaps the most charismatic of these is theBurrowing Owl.

Few birds will bring birders screechingtheir cars to a halt faster than will a Bur-

rowing Owl perched quietly on a fencepost,or peering quizzically out of a prairie doghole. Whether standing solemnly beside aprairie dog hole, or perched on a low fence-post, a miniature owl standing erect and inplain view during the middle of the daysomehow seems to be such an unlikely ap-parition that it requires prolonged and ex-tensive study. There is something in the an-imal’s intense yellowish-green eyes thatdemands to be watched with equal inten-

sity, and the Burrowing Owl’scomical, not-quite-erect stance

might remind one of aspindly-legged, feather-cladleprechaun still trying torecover from last night’shangover. The seeminglycurious if not actuallyfriendly manner of the

Burrowing Owl when ap-proached by humans is

probably the reason that insome parts of the American West

the species is known as the“howdy” owl.

The usual rules of owl decorumdo not apply to Burrowing Owls.

First, they are not as highlynocturnal as most other

owls, but instead are ac-tive mainly during broad

daylight. In fact, their retinas lack the re-flective surface that increases nocturnal vi-sual sensitivity and produces the “eyeshine” typical of most owls. Secondly, un-like the larger owls of the grasslands, Bur-rowing Owls are surprisingly insectivo-rous, at least during the summer months

G R A S S L A N D B I R D S

Paul A. JohnsgardSchool of Biological Sciences

University of Nebraska

Lincoln, Nebraska

68588-0118

pjohnsga@unlserve.unl.edu

W W W . A M E R I C A N B I R D I N G . O R G 41

Unlike most owl species, the charismatic Burrow-ing Owl is diurnal. With a little bit of patience, thebirder can observe various aspects of this bird’selaborate behavior and complex ecology. ArapahoeCounty, Colorado; July 1990. © D. Robert Franz.

when large, slow-moving insects, such as dung bee-tles (Scarabaeidae spp.) and ground beetles (Cara-bidae spp.), are abundant around dog towns and areeasily captured. Thirdly, Burrowing Owls seem tolack the acute binaural hearing and precise sound-source localization abilities that owls as a group areprimarily noted for, and instead appear to rely ontheir keen daytime vision for prey-finding. In corre-lation, their faces have only poorly developed facialdisk feathers surrounding their ears, which help fun-nel extremely faint sounds into the ear canals of themost highly nocturnal owls.

When a Burrowing Owl is confronted by an ap-proaching human, it is more likely to stay put than tofly away immediately. Often, after a few slight hori-zontal or vertical head movements by the bird, as iftrying to shake its head clear of a foggy memory, butwhich are probably designed to get a better distance-estimating fix on the new intruder into its personalspace, the owl will probably duck back into its hole.Or, if perched on a post, it may take silent flight overthe prairie dog town and land near its burrow en-trance. When cornered in its burrow, a BurrowingOwl will produce a sound that mimics a rattlesnake’srattle, and at such times may also spread and tilt itswings vertically, apparently to make itself appearlarger and more dangerous. The male’s courtship callis usually soft and owl-like, but adults of both sexesalso utter a rapid chatter when alarmed or while de-fending the nest.

Although a Burrowing Owl is perfectly content totake over a prairie dog burrow without making majorstructural changes or other renovations, it is likely togather fragments of dried bison or cattle dung, breakthem into small pieces, and line the entrance area infront of its burrow with these bits of debris. Suchmarkings help one to recognize an active BurrowingOwl burrow, as do the dried owl pellets that are usu-ally rich in chitinous insect fragments such as the

“They can burn grasses with their stare. Yellow eyes magnifyinglight.” So writes Terry Tempest Williams of the Burrowing Owl,

in her book Refuge. Kansas; October 2001. © Bob Gress.

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undigested exoskeletal remnants of grasshoppers and scaraband carabid beetles.

The biological function of the scattered ungulate droppingsis uncertain, but they may help mask the odors of an activeowl burrow, for Burrowing Owls are highly vulnerable tobadgers (Taxidea taxus). In a 1989 study, Gregory Green andRobert Anthony found that, next to desertion, badgers werethe most significant source of Burrowing Owl nesting mortal-ity, but that nests lined with livestock dung were significantlyless susceptible to predation than were unlined nests. Addi-tionally, it has been suggested that the presence of dung mayhelp attract dung beetles to the nest, where they can be easilycaptured by the owls.

The Burrowing Owl is the only strongly migratory owl ofthe northern plains, presumably because its insect foods be-come progressively unavailable in fall. Then it turns increas-ingly to relatively small rodents such as pocket mice (Het-eromyidae spp.) for food. Although small mammals and birdsmake up a low percentage of the summer diet as measured bytheir sheer number (about 5–20%), the much larger bodymass of mammals relative to insects tends to make mammalscomprise the predominant portion (about 80–95%) of the bio-mass of all foods taken. Frogs, toads, lizards, snakes, and eventurtles have also been reported as Burrowing Owl fare, as wellas birds at least as large as Horned Larks (Haug et al. 1993).There is also some hunting activity at night, especially duringbright moonlit nights,and at these times smallnocturnal rodents suchas voles and pocket micewould be the most likelytargets. Ray Poulin(2003) determined thatin Saskatchewan the pri-mary owl foods are deermice (Peromyscus spp.)and meadow voles (Mi-crotus spp.), and theonly year that the owls

showed a population increase was following a peak in volepopulations.

Besides using prairie dog burrows, Burrowing Owls havealso occasionally adapted to living in burrows made by groundsquirrels, marmots and woodchucks (Marmota spp.), badgers,foxes, coyotes, skunks, nine-banded armadillos (Dasypusnovemcinctus), kangaroo rats (Dipodomys spp.), and tortoises.They may also dig their own burrows in the absence of avail-able housing already provided by burrowing mammals. Theyhave even been known to use natural rock cavities and to ac-cept human-made artificial burrows where natural excava-tions are not possible.

On the Great Plains, it is primarily the black-tailed prairiedog that offers the owls housing. It has been estimated that 95percent of all the Burrowing Owls nesting on the Comanche,Cimarron, Rita Blanca, and Kiowa National Grasslands, all lo-cated in the southern Great Plains, were directly associatedwith prairie dog towns, according to an unpublished study byShawn Conrad, Jennifer Dose, and Dan Svingen. Only three of114 prairie dog towns supporting Burrowing Owls lacked ac-tive prairie dog burrows, indicating the importance of “dog”activity in making good owl breeding sites. The three inactivetowns supporting Burrowing Owls had apparently been inac-tive for only one year. Likewise, among 543 Burrowing Owlnests found in the Oklahoma Panhandle, two-thirds were lo-cated within black-tailed prairie dog colonies (Butts and Lewis

1982). Besides being able to exploit inactive dogburrows, the owls favor the combination of lowshrub coverage, short vegetation, and high per-centage of bare ground that is typically present inprairie dog colonies. When the ground-level vi-sion is variously obstructed, the birds find suit-able nearby observation posts to use, such asfenceposts or boulders.

Within prairie dog towns, Burrowing Owls fa-vor larger and active colonies; typically, a townthat has been abandoned by prairie dogs will alsobe abandoned by Burrowing Owls within threeyears, perhaps largely as a result of encroachment

B U R R O W I N G O W L

The black-tailed prairie dog (inset) is a so-called “keystone species”, meaning thatnumerous other species in the environment depend upon its presence. The Burrowing

Owl, which nests and roosts in prairie dog burrows, is one such dependent species.

Fort Niobrara National WildlifeRefuge, Nebraska; June 2004.© Paul A. Johnsgard.

Fort Niobrara National WildlifeRefuge, Nebraska; June 2004.© Paul A. Johnsgard.

Boulder, Colorado; October 2004. © Bill Schmoker.

W W W . A M E R I C A N B I R D I N G . O R G 43

of dense vegetation, but also because of the gradual dete-rioration of the burrows themselves. Within active towns,the owls often choose nests near the periphery of thecolony, where there may be a greater abundance of in-sects, more available nearby perches, and a proximity toforaging areas. Burrowing Owls may also favor sites offer-ing several “satellite” burrows, used by both adults andyoung, perhaps to avoid the buildup of nest parasites andloss of an entire family to predators. As many as five suchsatellite burrows may be used by a single owl family,which may contain a half dozen or more owlets of vary-ing ages and sizes.

For the Great Plains as a whole, Burrowing Owl occu-pancy rates of active prairie dog colonies are substantial-ly lower in the northern Great Plains national grasslandsthan in those of the southern Great Plains (Sidle et al.2001). Regardless of geographic location, BurrowingOwls were found in one study to use active dog towns ata rate 6.3 times greater than at inactive ones, evidencingthe need for active prairie dog colonies to maintain breed-ing habitat for Burrowing Owls. The presence of live prairiedogs not only means that there will be a ready supply of new-ly abandoned but structurally intact burrows available to theowls, but also that the owls may exploit the efficient warningsystem of the prairie dogs. There is no proof that prairie dogsdirectly benefit from the presence of Burrowing Owls, and theever-alert rodents sometimes utter alarm notes when the owlsfly overhead, suggesting that prairie dogs are at least some-what wary of the owls.

Where to Find Burrowing OwlsBirders who want to see Burrowing Owls firsthand in theGreat Plains region have many choices. In Canada,Saskatchewan Landing Provincial Park andGrasslands National Park offer possibilities.In Montana, there are Bowdoin, Charles M.Russell, and Medicine Lake NationalWildlife Refuges, as well as the National Bi-son Range and the difficult-to-access ULBend National Wildlife Refuge. In NorthDakota the Little Missouri National Grass-land and Theodore Roosevelt National Parkare good choices for owl-watchers. In SouthDakota, Badlands and Wind Cave NationalParks, Buffalo Gap and Fort Pierre NationalGrasslands, and Custer State Park are all ex-cellent choices. Nebraska’s Fort NiobraraNational Wildlife Refuge usually has Bur-rowing Owls visible near the refuge head-quarters, but to placate ranchers with graz-ing interests, prairie dogs are still beingpoisoned on most state and federal lands inNebraska, including the Oglala National

Grassland. In Wyoming, Thunder Basin National Grassland isa potential site for Burrowing Owls and other shortgrass fau-na, although prairie dog poisoning is being carried out there,too. In Kansas, Prairie Dog Lake State Park and Smoky ValleyRanch have Burrowing Owls, and they are also relatively com-mon on Cimarron National Grassland. However, many Kansascounties have mandatory prairie dog eradication programs,and Burrowing Owls are now essentially limited to the threewesternmost tiers of counties.

There are progressively more Burrowing Owls to be found asone moves into the southwestern plains. In eastern Colorado,Comanche, Cimarron, and Pawnee National Grasslands allsupport Burrowing Owls, as does the Rocky Mountain Arsenal

Although Burrowing Owl families may be found anywhere in a prairie dog colony,the preferred location for nest-placement seems to be along the outskirts of the“town”. Keith County, Nebraska; June 1980. © Paul A. Johnsgard.

Burrowing Owls are tolerant of human presence, and small colonies are often found near golf courses, housingdevelopments, and agricultural fields. But the species is threatened by outright habitat destruction, along withcontinuing persecution of black-tailed prairie dogs. Arapahoe County, Colorado; July 1989. © D. Robert Franz.

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National Wildlife Refuge near Denver. In Oklahoma,Black Mesa State Park and Optima, Salt Plains, Washita,and Wichita Mountains National Wildlife Refuges allhave breeding Burrowing Owls. The species is fairlycommon at Bosque del Apache, Bitter Lake, and Las Ve-gas National Wildlife Refuges in eastern New Mexico.Burrowing Owls are also common in Texas at BuffaloLake and Muleshoe National Wildlife Refuges, and atRita Blanca National Grassland.

The Florida population is of a different and sedentarysubspecies (floridana; the widespread western sub-species is hypugaea), and other resident races also occurin the West Indies. One population estimate for Floridais 3,000–10,000 adults (Haug et al. 1993). In Florida,the owls typically dig their own burrows, although thegopher tortoise (Gopherus polyphemus) is a potentialsource of ready-made burrows. Population data forFlorida do not show statistically significant trends, but theFlorida population has fairly high adult annual survival andbreeding success rates, with a few known cases of two broodsbeing produced in a single year.

The species is now classified as Nationally Endangered inCanada. T. I. Wellicome and E. A. Haug estimated (1995 re-port to Committee on the Status of Endangered Wildlife inCanada) the mid-1990s population for the Canadian prairieprovinces at between 1,010 and 1,685 pairs, with 5–10 addi-tional pairs in British Columbia as a result of reintroductionefforts there. Burrowing Owls are classified as NationallyThreatened in Mexico, although their numerical status there isunknown. The species also occurs in Central American grass-lands, in South America from Venezuela to Tierra del Fuego,and locally in the West Indies.

Returning to western North America, the Burrowing Owl isstate-endangered in Minnesota, is threatened in Colorado, andis considered to be a species of concern in seven additional

states. A range-wide survey of BurrowingOwl populations by James and Espie

(1997) suggested that as of the early1990s there may have then been20,000–200,000 breeding pairs inthe United States. In the GreatPlains, Texas had an estimated

population in excess of10,000 pairs in the 1990s,and states with popula-tion estimates of 1,000–10,000 pairs were Col-orado, New Mexico, Wyo-ming, and Nevada. Stateswith 100–1,000 estimat-ed pairs included Kansas,Montana, Nebraska, NorthDakota, Oklahoma, andSouth Dakota. BurrowingOwls have been essential-ly extirpated from Iowa.In western Nebraska onepopulation study (Des-mond and Eskridge 2000)

indicated that a 58% population decline of Burrowing Owlsoccurred between 1990 and 1996, during a period of intensiveprairie dog poisoning and their associated rapid populationdeclines. Although there have also been some apparent re-gional increases in the southwestern desert grasslands and theinterior northwestern grasslands, the greatest declines haveoccurred in the northern Great Plains. Sadly, the familiar“howdy” owl of the plains is in increasing danger of having tosay “adios” to much of western North America.

Literature CitedButts, K.O., and J.C. Lewis. 1982. The importance of prairie dog towns to Burrowing

Owls in Oklahoma. Proceedings of the Oklahoma Academy of Science 62:46–52.

Conrad, S.T., J.L. Dose, and D.N. Svingen. Burrowing Owl Association with Prairie Dog

Towns in the Southern Great Plains, unpublished manuscript. U.S. Forest Service,

Springfield.

Desmond, M.J., and K.M. Eskridge. 2000. Correlations between Burrowing Owl and

black-tailed prairie dog declines: A 7-year analysis. Journal of Wildlife Management

64:1067–1075.

Green, G.A., and R.G. Anthony. 1989. Nesting success and habitat relationships of Bur-

rowing Owls in the Columbia Basin, Oregon. Condor 91:347–354.

Haug, E.A, B.A. Millsap, and M.S. Martell. 1993. Burrowing Owl (Athene cunicularia), in:

A. Poole and F. Gill, eds. The Birds of North America, no. 61. Academy of Natural

Sciences, Philadelphia, and American Ornithologists’ Union, Washington.

James, P.C., and R.H.M. Espie. 1997. Current status of the Burrowing Owl in North

America: An agency survey, pp. 3–5 in: J.L. Lincer and K. Steenhof, eds. The Bur-

rowing Owl: Its Biology and Management, Including the Proceedings of the First

Burrowing Owl Symposium, research report no. 9. Raptor Research Foundation,

Boise.

Poulin, R.G. 2003. Relationships between Burrowing Owls (Athene cunicularia), Small

Mammals, and Agriculture, dissertation. University of Saskatchewan, Regina.

Sidle, J.G., M. Ball, T. Byer, J.J. Chynoweth, G. Foli, R. Hodorff, G. Moravek, R. Peterson,

and D.N. Svingen. 2001. Occurrence of Burrowing Owls in black-tailed

prairie dog colonies on Great Plains national grasslands. Journal of Raptor

Research 35:316–321.

B U R R O W I N G O W L

Although the Burrowing Owl remains wide-spread in North America, with populations scat-

tered throughout the West and anisolated population in Florida, the

species is in overall decline. Thegreatest declines have occurredin the northern Great Plains.Arapahoe County, Colorado; July1990. © D. Robert Franz.

During the summer months, the Burrowing Owl’s dietconsists mainly of arthropods. Arapahoe County,Colorado; July 1990. © D. Robert Franz.

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